<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../vue.js"></script>
</head>
<body>
    <div id="app">
        <input type="text" v-model="value">
        <h1>{{value | filter1}}</h1>
    </div>
</body>
<script>
    var vue =new Vue({
        el:'#app',
        data() {
            return {
                value:''
            }
        },
        filters:{
            filter1(value){
                return value.split(' ').join('')
            }
        }
    })
</script>
</html>